Dysembryoplastic neuroepithelial tumour

A type of brain tumor

Dysembryoplastic neuroepithelial tumour
DNET HE.jpg
Micrograph of a DNET. H&E stain.
Synonyms	DNET
Specialty	Neurosurgery, Neurology, Oncology
Symptoms	Seizures (especially drug-resistant epilepsy), headaches, cognitive or behavioral changes
Complications	Intractable seizures, neurological deficits if untreated
Usual onset	Typically during childhood or adolescence
Duration	Chronic, may be stable over time
Types	Simple, complex, and nonspecific forms (based on histological features)
Causes	Congenital malformation; exact cause unknown
Risk factors	Possibly related to abnormal neural development
Diagnosis	MRI, biopsy, histopathology
Differential diagnosis	Ganglioglioma, oligodendroglioma, astrocytoma, low-grade glioma
Prevention	None known
Treatment	Surgical resection (curative in most cases)
Medication	Antiepileptic drugs (for seizure control)
Prognosis	Excellent after complete surgical removal; low risk of recurrence
Frequency	Rare
Deaths	Very rare; typically benign

Dysembryoplastic neuroepithelial tumour, MRI FLAIR.

Dysembryoplastic neuroepithelial tumour (DNET) is a rare, benign brain tumor that is typically associated with epilepsy. It is classified as a glioneuronal tumor, which means it contains both glial and neuronal elements. DNETs are most commonly found in children and young adults and are often located in the cerebral cortex, particularly in the temporal lobe.

Pathophysiology

DNETs are thought to arise from abnormal development of the neuroepithelium, the tissue that gives rise to the central nervous system. These tumors are characterized by a specific histological pattern, which includes the presence of "floating neurons" in a myxoid background and columns of glial cells. The exact cause of DNETs is not well understood, but they are considered to be developmental lesions rather than true neoplasms.

Clinical Presentation

Patients with DNETs typically present with seizures, which are often the first and only symptom. The seizures are usually focal and may be resistant to antiepileptic drugs. Other symptoms depend on the tumor's location and may include headaches, nausea, or neurological deficits.

Diagnosis

The diagnosis of DNET is primarily based on magnetic resonance imaging (MRI) findings and histological examination. On MRI, DNETs appear as well-circumscribed, cortical lesions that may have a "bubbly" appearance due to their cystic components. Computed tomography (CT) scans may show a hypodense lesion without significant enhancement. Definitive diagnosis is made through biopsy and histopathological analysis.

Treatment

The primary treatment for DNET is surgical resection. Complete removal of the tumor often results in seizure control and is considered curative. In cases where the tumor cannot be completely resected, additional treatments such as antiepileptic drugs or vagus nerve stimulation may be used to manage seizures. Radiation therapy and chemotherapy are generally not indicated due to the benign nature of the tumor.

Prognosis

The prognosis for patients with DNET is generally excellent, especially when the tumor is completely resected. Most patients experience significant improvement in seizure control post-surgery. The risk of malignant transformation is extremely low, and long-term survival rates are high.

Related pages

• Epilepsy
• Glioneuronal tumor
• Neuroepithelium
• Seizure
• Magnetic resonance imaging